Electric signaling apparatus for railways and the like



July 20 1926.

J. GARDNER ELECTRIC SIGNABING APPARATUS FOR RAILWAYS AND THE LIKE Filed August 18, 1920 2 ShletI-Shnt 1 Inventar:

July zo 192e. 1,593,253

J. GARDNER ELECTRIC SIGNALING APPARATUS FOR RAILWAYS AND THE LIKE Filed August 18, 1920 2 sheets-sheet 2 j /a J.

Inventor;

Patented July 20, 1926.

UNITED STATES PATENT FFEQE.

JOI-IN GARDNER, 0F CARNFORTH, ENGLAND, ASS1GNOR TO THE GENERAL ELECTRIC COMPANY LIMTED, 0F LONDON, 4EN('TFLAND.

ELECTRIC SIGNALING APPARATUS FOR RAILWAYS AND THE Application led August 18, 1920, Serial No.

This invention has reference to electric indicators iter railways and the like, and it has for its object to provide an improved indicator to indicatie the progress oit railway and like vehicles along a track or permanent way, and whether any section is or is not occupied by a train.

.According to this invention.` the indicator comprises two independent electrolnanjnetic coils or windings having a common armature or the like and each of which is adapted when energized to give rise to a magnetic field capable oitl attracting the single armature or the like when the other coil or winding is partially or completely cle-energized, in which attracted position the armature or the like remains until the iniiuencing coil or winding is partially or completely cle-energized.

Two arrangements ot apparatus in accordance with the invention are illustrated in the accompanying' drawings, whereof Fig. 1 represents one arrangement in which the electromagnetic receiving instrument embodying a transversely movable part is shown in end view partly in section and the electrical circuits including the transmitter .instruments and other parts are illustrated diagrammatically, Figs. 2 and 3 respectively are side elevation and plan, partly in section, of the electromagnetic receiving instrument shown in Fig. 1. Fig. 4 is a view similar to Fig. 1 ot an alternative arrangement wherein a movable part or armature moves to and from the ends ot the electromagnets. Figs. 5 and 6 respectively are sectional side elevation and plan of one form of transmitter instrument, and Fig. 7 is an end View of part et the same.` i l Referring lirst to Figs. 1, 2 and 3, the receiving instrument therein illustrated comprises two electro-magnets e, al, an arm, pointer or needle 7), and a movable part or armature c which is con,- neeted with the latter or forms a part thereof and is adapted to be operated either of the electro-magnets to move the pointer or needle to either of the dotted positions shown in Fig. 1. The coils or windings oit the electromagnets (i, al are attached to a single yoke member d in which is mounted or carried one adjustable endpivot el of an arbor e, the other end pivot e2 being ad- 404371, and in Great Britain August 21, 1919.

justably mounted in a bracket f on a base f1 ot non-magnetic material to which the yoke member (Z is attached. The arbor e supports the arn'iature or movable part c and is of greater diameter than is usual where a horseshoe magnet consisting of two coils or windings in series is en'lployed, in order that it may serve as part ot the magnetic circuit Vior the two independent magnets a., a?. By mounting the armature or movable part as described, it is adapted to move transversely to the axes of the cores oit the electromagnets a, al and a gap oi more than usual dimensions can be provided between 'the poles oi: the magnets and such armature or movable part.

The pointer or needle b is adapted to operate in conjunction with a dial inscribed as indicated in Fig. 1, with the custon'iary characters, e. Line clear and Train on line, and to either ot these positions it is moved by the electromagnets a, al when one ot them is (le-energized, or is energized to a greater extent than the other. The -electromagnets are controlled by two trans mit-ters g, g1 which are so disposed relatively to a railway track as to be inliuenced by the passage oit a train thereover. Such initiuence has iter effect to partially or completely deenergize either ot the magnets by partially or wholly interrupting the circuits thereof and thus enables the moven'ients oic the needle or pointer l) to be eliected automatically. rl'he two transmitters g, gl are connected in normally closed circuits in series with the respective eleetromagnets a, al, each of which is adapted7 when energized, to give rise to a magnetic field capable of attracting the single armature or movable part c from a position somewhat beyond a point midway between the two windings or magnets, while the armature is so suspended en the arbor e as to move to a central position midway be tween the electromagnets when neither et the magnets is energized, thereby indicating thro-ugh the pointer or needle 7) that the needle instrument is out of use or is not working, such as, e. by the words Line closed, The needle or pointer may be rigidly secnred to the armature or movable part., or it may be otherwise connected. therewith so as to follow the movements thereof, or the armature may serve as the indicator.

LSU

The circuits of the electromagnets ci, a1 and the respective transmitters g, gl comprise a common source It ot electric current, leads y', jl from the source h, to the magnets of, al respectively, leads le, lc1 from the magnets to the transmitters, and lea-ds m, 'rn/1 cfrom the transmitters to the common source 7L.

The transmitters g, g1 may be of any desired type adapted to permit or canse a cessation or diminution ot .electric current in a normally closed circuit. 'preterred type of transmitter insnument is shown in Figs. 5, 6 and and comprises two .parallel and substantially thick brass or other suitable metallic strips, bars or reeds g2, g" which are heldat one end horizontally and gripped between two metal discs gt, g"v secured to the bottom ot the casing The reeds g2, g3 are insulated from each other and 'trom the discs gi, gf bymica or like insulating ma terial which will freely t ansmit to the reeds any vibrations communicated to the casing The reeds are so twisted or shaped that when viewed from their free 4ends as shown in Fig. 7, they resemble a broady letter l! with the limbs downwardly inclined l\to wards each other at an angle Aof about 900 and separated rat Vtheir lower edges. Two flat carbon -or other electrodes g, gS are so arranged. on the upper inner faces o't the reeds between Vthe Anodes and antinodes thereof as to ,form an open bottom fi shaped gap, andlon such electrodes arranged Vparallel to the reeds alight and 7freely movable cylindrical carbon :rod g which is small enough to rest at the bottom of the gap between .the electrodes gl, g3 without passing through the same, and is provided with enlarged ends to prevent longitudinal displacement from between the electrodes wljien in use, and serves as the only means oli' electrical connnunication ,between the electrodes gi, g3. The leads 7c, /cl and. in, ml from the m gnets a, all and to the source 7L oit electric current, respectively, are connected with the reces g2, g3 of the transmitters g', g1 at gm and g, and the circuit is bv way ol" one reed gL through the electrode gT thereon, then tlirough the rod gg, .the other electrode g8. and the reed giS on which the latter rests.

The reeds g2, g3 are ot such a nature' as to be atl'ected by mechanical vibrations communicated to railway sleepers, to ywhich the traiismitters are secured, by the passage ot a trainvover the rails, the vibrations passing trom the sleepers to the reeds by wav of the nodes thereof. .l

To enable each transmitter to be so adusted Vas to be responsiye to certain vibra tions only,l such as e. g. those a train passingr` over a sleeper on which the instrument placed, .and not responsive to other like vibrations ot' less degree, such as e. those caused by a train. passinen over an a liacent track, there is included in the electrical circuit oit each transmitter a variable resistance gigas shown in Figs. l and 4 adapted to be adjusted tor this purpose.

las an alternative to the carbon rod g"` there may be employed one or more balls et conducting material.

In the circuits or the transmitters g, gl interrupting` keys a, nl may be provided for manually interrupting the circuits to cew energize the magnets a, al when desired, and there may also be provided in the circuits switches 0, ol which can be closed across the terminals j), p1 and g, gl to complete the circuits through the magnets 0 al and the transmitters g, g1 or across the terminals 19, p2 and g, g'z to short` circuit or cut out the transmitters g, g1.

`For convenience o'l" imderstanding in the following` d iiption of the operation ot the apparatus, the transmitter grwhic'h is arranged at the commencement of the s l tion ot track concerned and is acted upon by the train at the moment ot' entering the section, referred to as the enterine transinit-tei, and the transmitter gl which is a'aanged at'the end of the section and is acted upon by 'the train when leaving the section is referred to as Ythe leaving `transmitter. Similarly, the corresponding magnet-,` u, er' are rcierred to as the Lentering magnet77 and the leaving magnet respectively.

Normally, the switches 0, 01 will be closed across the terminals p, 791 and g, g1, respectively, to complete the circuits through the magnets a, al andv their coi'nplementary transmitters g, lgl. vBoth magnets a, all will 'be energized to a like extent and exert a similar e-iiect on the armature c and the latter and the pointer b will occupy the midposition shown in Tull lines in Fig. l. When a `train enters the section of track concerned, the entering transmitter g will be influenced bythe vibrations set up in the track, thus reducing orY interrupting the current flowing through the entering magnet u, and partially or completely (le-energizing the latter. On the (le-energizing of the entering magnet a, the leaving magnet al ar tracts the armature c and 'the pointer moves to the right as shown in dotted lines, and shows the indication Train on line. Owing tothe ygreat gap between the armature 'c and the 'core of the entering magnet a, the armature continues to be attracted by the leaving magnet and the pointer 'b to indicate rain on line until the train reaches the leaving transn'iitter g1 even though the entering transmitter may have previously become quiescent and the current Iflowing through, and the strength of, the entering magnet a been restored to the normal. llhen the train reaches the leaving transmitter gl this transmitter will be influenced by the vibrations set up by the train thus llll reducing or interrupting the current flowing through the leaving magnet al and partially or completely deenergizing the same and releasing the armature c which is then attracted by the entering magnet a and moves the pointer to the left as shown in dotand dash lines in Fig. 1, and gives the indication Line clear to show that the section of track concerned is no longer occupied by a train. The armature u* continues to be attracted by the entering magnet a and the pointer l) to indicate Line clear until the entering magnet a is algain partially or completely de-energized.

In the event of failure of the common source of electric current la both magnets a, a1 will be deenergized with the result that the armature c and pointer b will assume the middle-position illustrated in full lines and the indication' Line closed or some equivalent indication will be given to show that the apparatus is out of order. It will be observed that once the armature and pointer have been operated by one of the magnets a, al they continue to move from one extreme signaling position to the other unless both magnets are deenergized by failure of the common source of electric current or otherwise.

The interrupting keys n, nl are preferably controlled by springs a2 so that on the release of the keys after operation to interrupt' the circuits of the corresponding magnets a, all they automatically close the circuits of the magnets. Operation of the keys fn, in the circuit of the entering magnet a and transmitter g will by causing the corresponding signal or giving the corresponding indication give assurance as to the state of the distant transmitter and of the line, which may in some cases have a length of several miles, while the operation oi the key a1 in the circuit of the leaving magnet a1 and transmitter g1 will enable the operator to restore the apparatus to its normal state, after a train has entered the section of track, without waiting until the train has reached the leaving transmitter. Simultaneous operation of the keys n, nl enables the armature c and pointer b to move to the mid-position and the apparatus to be put out of use should this be required, and the apparatus may be retained out of use by retaining the keys n, nl in the operated position. The switches o, o1 enable either or both of the transmitters lg, g1 to be short circuited or cut out, in which case signals can only be given or an automatically given signal can only be cancelled by manual operation of the keys n, n1. Thus the invention provides, among other advantages, that the desired warning or signal shall be automatically caused by an approaching train while permitting cancellation of such warning or signal either automatically by the train or manually by the operator, as e. g by the gatekeeper at a level crossing.

In the arrangement of apparatus illustrated in Fig. 4, the magnets a, a? have separate portions 1", r1 for the magnetic circuits of the coils or windings so that the magnetic circuit of each magnet is separate from the circuit of other instead of the two magnetic circuits having a common return as in the previous arrangement. The movable part or armature c is pivoted at s and comprises two parts 01, c2 adapted to move to and from the ends of the poles of the magnets a, al respectively. The armature c may be given a bias towards central position such as by gravity acting upon a weight c3 depending from the armature below the pivot, and also if desired by a spring c4 acting between the weight c3 and the base f1 so as to assume that position in the event of failure of the common source of current. The arrangement illustrated in Fig. l is applicable in cases where the angular movement of the armature is small and the magnets act as a relay to control a local circuit containing a signaling device or indicator. The local circuit illustrated comprises a source of electric current t, a visual indicator u, a contact arm b1 carried by the armature c, leads 01 and w connecting the source t with the arm b1 and the indicator a respectively, and leads a? and y through which the circuit is completed through the indicator u by the arm b1 accordingly as the armature is attracted by the magnet a or the magnet al to lgive the corresponding indication.

In other respects, including its operation, the apparatus shown in Fig. 4- is the same as the apparatus illustrated in Fig. 1.

It will be understood that although only two arrangements of apparatus in accordance with the invention have been described in detail, considerable variations may be made without departing from the nature of the invention.

In most cases, the cut out switch 0 in the circuit of the entering magnet a and transmitter g may be dispensed with.

What I claim as my invention and desire to secure by Letters Patent is l. In a three position indicating device a pair of similar electro-magnets, a common current source to which said electromagnets are independently electrically connected, means in each of said connections for independently varying the strength of each magnet, an armature common to both electromagnets and biased to a position intermediate the electromagnets when both are deenergized, said armature being movable to one electromagnet and away from the other when the normal magnetic strength of said other electromagnet is reduced, the relation between the armature and the electromagnets being such that the armature is held by the e'lectromagnet to which it is moved after the strength of the other electromagnet is re stored to normal and until the inaiglietic etrength of the electromagnet to which it has heen moved is reduced.`

il ,ln a three position indicatingl device a pair of similar electro-macnete a common current source to which said electromagnets aire' indepenfflently electrically connected', means in each of said connections Jfor independently varying; the strength o'l? each magnet, an armature common to both electromagnets und stationary in an intermediate position hv' the eqirilized pull of thel electromagneteI 'd armature being` movable to one electronrwgnet and away from the other when the normal magnetic strength of said other electro-n'iafgnet` is reduced, the relaition between the armature and the electromagnets being such that the armature iS held by the electromagnet to which it is mos/'ed after the strength olg the other electromagn-et ie restored to normal and until the magnet strength of.' the electromagnet to which it hasbeen moved is reduced.

In a three positionindicatingl device a pair of Similar electro-magnets, common current source to which said electromagnete are iiulependentlv electrically connected, a device in each ot' saidconnectione capable, when subjected to vibrations, oi varying' the current passing to each magnet and there- :fore 'varying the strength of each magnet, an arma-ture common to both electromagnets and Said armature beingmovable to one electronnigjnet andv away from the other when the normal magnetic strength of saidv other electromagnet is reduced, the relation loetween the armatlue and: the electioliifagnets being euch that the armature is held by the ele'ctremagnet to which it is moved a'liter the strength oit' the other electromagnet is re :stored to normal and until the magnetic strength of the electromagnet to which it hac been moved is reduced.

fl. In a three positionindicating device a pair of similar electro-magnets7 a common current source to which said electromagnets are independently electrically connected, means in each ot said connectionel :lor norn1-alli,7 permitting the uniform passage of current but capable of varying the amount ot current passing, an armature common to both electromagnets,` said armature being nioahle to one electromagnetand away from the other when the normal magnetic strength et cnid other electromagnet is reduced, the relntionvhetn'een the armature and the electromagnete being such 'that the armature is held h v the electromagnet to which it is moved after the Strength of the other electromagnet ie. reetored to normal and until the :magnetic Strength of the electromagnet to ul'iichit has heen moved is reduced.

ln Witness whereof I have hereunto set my hand.

Jol-1N GARDNER. 

